Pinyin words should be entered without spaces, either with or without tone numbers: ni3hao3 or nihao.
The character ü can be entered as v instead.

The asterisk character * can be used as a wildcard to match zero or more characters:

rest* will match any word starting with rest, such as restaurant or restrain*文 will match any word ending with 文, such as 中文 or 英文b*g will match any word starting with b and ending with g, such as big or boring*中国* will match any word containing 中国, such as 传统中国医药 or 中国人民

Double quotes " " can be used to group search terms together:

"to rest" will only match entries where to and rest directly follow eachother

The minus symbol - can be used to find entries without a certain search term:

Chaoyang district in east and northeast Beijing, a county level district of Beijing municipality / Chaoyang prefecture-level city in Liaoning province 遼寧省｜辽宁省 in northeast China / Chaoyang district of Changchun city 長春市｜长春市, Jilin / Chaoyang county in Chaoyang 朝陽｜朝阳, Liaoning